It does not study wider conditions including a country's infrastructure, workforce skills, or security.

Hong Kong came in second place, with New Zealand third, and the US behind the UK in fifth place. All of the top five remained in the same position as a year earlier.

Out of the 183 countries surveyed, the World Bank said 117 implemented new business-friendly regulation between June 2009 and May 2010 - the 12 months covered for the 2011 report.

The World Bank said governments were reacting to global economic circumstances.

"Against the backdrop of the global financial and economic crisis, policy makers around the world took steps in the past year to make it easier for local firms to start up and operate," said the report.

It added: "While some economies have been hit harder than others, how easy or difficult it is to start and run a business - and how efficient courts and insolvency proceedings are - can influence how firms cope with crises and how quickly they can seize new opportunities."

On a regional basis, the latest Doing Business report found that countries in Eastern Europe and Central Asia did most to make running a business easier in the 12 months covered, with 84% of countries carrying out at least one pro-business reform.

Kazakhstan, which recorded the most improvements worldwide, carried out several measures including amending its company law, streamlining business start-up procedures, and making it simpler to get construction permits.

East Asia and the Pacific was the next best performing region, with three quarters of all countries introducing at least one reform to make life easier for firms.

Latin America and the Caribbean saw the fewest improvements, with only 47% of countries introducing one or more pro-business measures.

Singapore's 'efficiency'

Report co-author Dahlia Khalifa told the BBC that Singapore continued to lead the way for a number of reasons.

The UK remains in fourth place in the global list

"Singapore has now been top of our survey for the past five years," she said.

"It is simply the most efficient place from which to import and export. For example, you only need four documents to export and import goods, which remains global best practice.

"Singapore is also the leader in protecting investors and minority shareholders."